TCAD Demonstration of a High-Voltage Lateral Double-RESURF-VLD β-Ga2O3 MISFET with p-type Diamond for Ultra-Low Ron,sp

In the design of power metal-oxide-semiconductor field-effect transistor (MOSFET) devices, balancing high breakdown voltage (BV) with low specific on-resistance (Ron,sp) remains a long-standing challenge. In this work, we proposed and simulated a novel Double-RESURF β-Ga2O3 metal-insulator-semiconductor field-effect transistor (MISFET) with varied-lateral doping (Double-RESURF-VLD MOSFET). By embedding alternating n-type and p-type pillar of diamond regions into the VLD channel, the Double-RESURF structure enables effective charge compensation, which allows higher drift-layer doping concentration without sacrificing BV, thereby significantly reducing Ron,sp. Simulation results show that the Double-RESURF-VLD MOSFET achieves a Ron,sp of 2.58 mΩ·cm², a reduction of more than 50% compared with 6.73 mΩ·cm² of the conventional VLD MOSFET. Meanwhile, the BV of the Double-RESURF-VLD MOSFET reaches 2.99 kV, representing a 30% improvement over the VLD-MISFET. In addition, the Baliga’s figure of merit (BFOM = BV²/Ron,sp) is improved to 3.47 GW·cm⁻², representing an increase of approximately 310% compared with 0.84 GW·cm⁻² of the conventional VLD-MISFET. These results demonstrate that the proposed Double-RESURF-VLD MOSFET offers a promising candidate for the next-generation of β-Ga₂O₃ power devices with superior trade-offs between BV and Ron,sp.